Ireland is heading up the investigation because Facebook's European headquarters are in Dublin.
Dado Ruvic/Reuters/Corbis

Ireland's data protection watchdog said Tuesday that it will investigate Facebook over the user data it transfers from Europe to the US.

The probe will examine whether Facebook adequately safeguards the data of European citizens who use the social network, including whether that data is accessible to the US government and the National Security Agency. Facebook, based in Palo Alto, California, has its European headquarters in Dublin, which is why the investigation is taking place there.

The investigation was sparked by a landmark ruling earlier this month by Europe's highest court that invalidated a 15-year-old pact known as "Safe Harbor." The pact has been used by over 4,000 US businesses, including Facebook, to transfer data from the European continent. It had allowed companies to send user data to the US without guaranteeing the information would be protected from the eyes of the US government.

Findings against Facebook could ultimately force the world's largest social network to change the way it handles data in Europe. If the company is found not to have adequate safeguards in place, the Data Protection Commissioner may decide whether to suspend Facebook's data transfers back to servers in the US. European users of the social network would not see any change in their day-to-day experience using the social network.

"Facebook is not and has never been part of any program to give the US government direct access to our servers," said a Facebook spokesman in a statement to CNET. "We will respond to enquiries from the Irish Data Protection Commission as they examine the protections for the transfer of personal data under applicable law."

Irish Data Commissioner Helen Dixon previously said she would not investigate complaints about Facebook's data transfers because they were covered by Safe Harbor. On Tuesday, she told the High Court in Ireland that an investigation would go ahead, in light of Safe Harbor being ruled invalid and because of recommendations from the European Court of Justice.

"My Office will now proceed to investigate the substance of the complaint with all due diligence," Dixon said in a statement.